Precision-threading lathe



June 25, 1929. P. M. MUl-:LLER

PRECISION THREADING LATHE Filed July 9', 192s 2' Sheets-Sheet 1 O -Yll O -June 25, 1929. P. M. MUELLER PREGISIO THREADING. LA'lfHE Filed July 9, 1926 2 Sheets-Sheet 2 /NvE/Jro Wmmum b" /f Arm rl Paume 2s, 1929.

l 1.713.480." .uNiTED- STATES PATENT OFFICE.

:PAUL n. numana, or marroni, eoNNncrIeur, AssIeNoa 'ro nur a wm'nmr j conm, oir im'w Yoan, N. Y., a conrom'rron er maw maaar.'

nnEcIsIoN-Tnnnanme Lnrnnl Application led Juli, 1928. Serial llo..121,388..

This inventionelates to lathesand par; ticularly to a lathe adapted for precision threading operations. l An object of the present invention is to 5 provide a lathe with special means for per-4 orming screw threading operations whereby the lead of the work threaded my be cut toa very high degree of precision.

vide a lead screw for a lathe the threaded portion of which is materially shorter than the length of the bed of the lathevso that in performing threading operations substantially the saine portions of the threads may ll be used with the tool carriage adjusted to any osition along the bed for bdifferent 'len s of or positions'of'the threads on the work.

Another object of the invention is to proy Another object of the invention is to provide a lead screw having threaded portions at one end engaging a rotatable nut in the lathe `headstock and a sleeve rotatably mounted thereon and" preferably secured thereto by threads at the opposite end of the lead screw of a different lead and of o posite hand than the lead of the threads on t e lead screw, and also to provide clamping means for the tool carriage securing it to the sleeve at any desired point along the sleeve.

Another object of the invention is to provvide a rotatable nut driven from connections extending from the. work spindle for effect ing longitudinal movements of the 'tool in timed relation to therotation of the work A and to the le screw during the vaixial'moveri'ients of the carriage,

vWith-these and other objects in view, my inventionconsists in the features of construction and operation set forth'in the following specification and illustrated in the accompanying drawings.

the accompanying drawings annexed hereto and forming a part of this specification, I have shown my invention embodied in an engine lathe but it will be understood Anotlier object of the inventiony is to pro-- rovide means for slightly rotatingL l member enga that the invention can be otherwise em. bodied and that the drawings are not to be construed as defining or limiting the scope of the invention, the claims appended to this specification being relied lupon for 'that pur-v pose.

In the drawin Y Figure' 1 is a ront elevation of a complete machine providedfwith the present invention. Fig. 2 1s an enlarged view in front elevat'ion of the heads'tock ofthe lathevandadja- .cent parts, parts being broken away vto more clearly disclose the construction. Fig. 3 is an endelevation of the machine taken from the left-hand end of 2. i.

Fig. 4 is a front elevation of the tailstock end of the lathe partially broken' away to show the parts thereof in section.

Fig. 5 is a plan view-.of the lead com envsating mechanism at the tailstock end o the lathe.4 l

Fig. 6 isaplan view of the adjustable compensating member, and Y Fig. Z is a cross sectional view of the clamping mechanism taken v substantially :along line 7'-7 o'f Fig. 1.

In the above mentioned drawings I have shown but one embodiment of the invention which is now deemed nreferable, but it is to be understood that Ac tions ma be made within the scope of the spirit of the invention.

nges and modifica` i Briefly andfinits broadest aspect, my invention vcomprises the followingV principal parts: First, a base; second, a hea aving work supporting and rotating means" thereon; third, a tool supporting carriage slidably mountedalong the base; fourth, a threaded member rotatabl mounted adjacent the headstock and a a ted to be held against axial ovement; fift ,means for ro tating this me b'er in predetermined timed relation to the'work supporting and rotating means; sixth, a cooperating threaded ging said first mentioned threaded member and extending along the base;isevent h, a sleewe rotatab y mounted upon the cooperating threaded member and threadedly` connectedlthereto; eighth, an

angularly adjustable 'plate mounted adjacent the tailstock; nin air -arin on said eooperating threaded member adapted to engage a slot in said angularly adjustable 85 appende claims without departing from the plate; and tenth, means to Yclamp the tool support to said sleeve in any position of the carriage.

Referring more invdetail to the figures of the drawings, I provide a base 10 having a headstock 11 ixed thereon at one end and a 'tailstock 12 adjustably mounted along' suitable ways 13 formed on said base 10. With- -in the headstock 11 is a work supporting and rotating member preferably in the form 'of a spindle '14 which may be rotated at a the interme iate drivingfshaftsl?nL forthe work supporting and rotating spindle 14 so that thiselongated member 16 and =its threaded member 15 may be rotated in timed `relation to the work rotating spindle 14. It will be understood that these change gears order to enable the nut 15 to be rotated in different predetermined relation to the rotative movement of the spindle 14.

Adapted to engage the threaded portions of the nut 15 is a lead screw 20which extends along the base. Normally this lead screw 20 is not rotated but is axially moved due to the rotation of the nut 15. In order to perinit axial movement of this `lead screw 20, the elongated member 16 is bored throughout a major portion of its length so that the lead 'screw 20 can enter. Adapted to engage this lead screw 20 beyond its threaded lportion in a manner to be more particularly described later, is a tool carriage 21 on which may be mounted a conventional or other l form of threading tool 22. I twill be seen from the above mechanism thatrotation of the work spindle 14 will rotate the nut 15 and thus axially move the lead screw-"20 in one direction or the other and that with the toolcarriage 21 clamped to the lead screw 20 threads on the work W will be Vformed of any predetermined lead. The lead, however, of'threa'ds, formed 'o the work W will reproduce any errors in the lead screw 20 and also will be limitedto a relatively few leads by the possible combinations ot change gears 18. In order to compensate `for slight errors in the lead screw 20 and to cut threads of slightly different leads, the following mechanism is provided.- Instead of clamping the tool carriage 21 directly to the lead screw 20, the lead screw 2,0 1s surrounded bymeans of a sleeve 25. It is this sleeve 25 which is clamped to the tool carriage 21 during the thread cutting operations. For this purpose a binding clamp 2Ga is provided in the apron of the tool carriage 21. The lead screw 20 extends throughout the length of this sleeve 25 and beyond its end is attached thereto by means of a nut 2G secured within the sleeve 25 and engaging supplementary threads 27 formed on the lead screw 20.l The threads 27 are preferably ofv the opposite hand from those in engagement with the nut 15 in order to increase the compensating or varying effect of the threading mechanism. Also mounted on the lead screw 20 and keyed thereto in fixed relation is a short arm 28 having a roller 29 at its outer end.

This'roller 29 on the arm 28 is adapted to engage within a slot 30 formed in an angularly adjustable plate 3l adapted to be secured in adjusted -position toA a bracket 32 adjacentthe tailstocl end ofthe base .10. It will therefore be seen from this construction that during the axial movement of the lead screw 20togetl1er with the sleeve 25 clamped ix) the tool carriage 21 the lead screw 20 ,will be slightly rotated `within the revolving nut 15 dependent upon the angular adjustment of the plate 31 carrying the slot 30. The ef- 18 may be of any predetermlncd ratios 1n?" fect of this rotation of the lead screw 2O will be to axially vary the position of the sleeve 25 and tool carriage 21 due to the threads on the nut 15, this axial movement or displacement takng place during the operative movements of the carriage 21. The compensating -or screw threads 27 connecting the lead screw 20 with the sleeve 25 will further axially displace the sleeve 25 and carriage 21, this supplementary displacement also taking place uniformly throughout the operative moveinents of the carriage 21. By suitably adjusting the plate 31 the resultant leads produced by the lead screw 20 and compensating or supplementary screw threads 27 and angular plate 31 may be of any desired distance and the number of different leads produced may be greatly increased over those produced by the lead screw 20 and the geared connections 18.

What I claim is:

1. A precision threading device for lathes comprising a base, work supporting and rotating means thereon, a tool carnage slidsupplementary tate said cooperating threaded member within said first mentloned threaded member during rotation of said first threaded member and axial movement of said carriage.

- 2. A precision threading device for lathes comprising abase, work sup orting and rotating means thereon, a too carnage slidable on said base, a nut rotated in timed relation to the work rotatin means and held in fixed axial position, a ead screw engaging said nut and normally held against ro tation, a sleeve surrounding an extended portion of said lead screw kand threadedly con'- nected thereto, means ri idly connecting said tool carriage to said eeve, and means to slightly rotate said lead screw within said nut and sleeve during -axial movement of said tool carriage.

3. A precision threading device for lathes comprising a base, work supporting and rotating means thereon, a tool carriage slidable on said base, a nut rotated in timed relation to the work rotating means and held in ixed axial position, a lead screw engaging said nut and normally held against rotation, a sleeve surrounding rsaid lead screw, the

lead screw being rotatable therein, means connecting said tool carriage to said sleeve at any point alon the length of the lead screw, an angular y adjustable late, and ,means engaging said plate to slightly rotate said lead' screw withinV saidnut and sleeve\'during axial movement of said tool carriage.

4. A- precision threading'Ik device for lathes comprising in combination, a base, work supporting and rotating means thereon, -a toolcarriage slidable on said base, a threaded member rotated in timed relation to the work and held in'fixed axial position, a cooperating threaded member engaging said `first threaded member and normally held against rotation, a sleevesurrounding said cooperatin threaded member and threaded- I ly attache thereto, means to clamp said carriage to said sleeve, andV means to slightly rotate the cooperating threaded member during the axial movement of the carriage.

signature.

In testimony whereof, I heretoatlix my 

